The present invention relates to a surface inspecting apparatus for inspecting the shape of the surface of an object to be inspected.
In a semiconductor manufacturing process, when a wafer coated with a photosensitive agent is to be exposed, a glass mask plate on which an IC circuit pattern is drawn is put to be adapted to the wafer and ultraviolet rays irradiates by an exposing device to transfer the circuit pattern onto the wafer. The circuit pattern drawn on the glass mask plate is reduced and projected onto the wafer. Therefore, a high flatness is required for the glass mask plate.
When the shape of the surface (the flatness of the surface) of the glass mask plate is to be inspected, there are the cases in which the glass mask plate is supported horizontally and in which the glass mask plate is supported vertically (including the case in which the glass mask plate is not supported perfect vertically). In the vertical support, an inspection with higher precision than that in the horizontal support can be carried out in the view point that the glass mask plate is deformed by its own weight with more difficulty than in the horizontal support.
In the conventional vertical support, however, since the glass mask plate is changed to be set from a horizontal supporting state into a vertical supporting state, the shape of a surface cannot be inspected with high precision by the influence of a deformation caused by its own weight in the horizontal supporting state or the influence of a deformation caused by a concentrated load on a support portion.